In the semiconductor processing industry, there is currently a strong trend toward scaling down existing structures and fabricating smaller structures. This process is commonly referred to as microfabrication. One area in which microfabrication has had a significant impact is in the microelectronic area. In particular, the scaling down of microelectronic structures is allowing the structures to be less expensive, have higher performance, exhibit reduced power consumption, and contain more components for a given dimension. Although microfabrication has been widely active in the electronics industry, it has also been applied to other applications such as biotechnology, optics, mechanical systems, sensing devices and reactors.
Microfabrication can be employed to fabricate permanent inexpensive rugged memory (PIRM) arrays. PIRM is an extremely low cost archival solid-state memory for digital photography, digital audio and other applications. From a fabrication perspective, PIRM includes a series of semiconductor and other thin-films sandwiched between a patterned top metal layer and a patterned bottom metal layer. Where these metal layers cross forms a two-port device. Imprint lithography is one type of fabrication method that is utilized fabricate these arrays.
Imprint lithography is typically utilized to pattern thin films on a substrate material with high resolution using contact between a master with the features of the structure to be fabricated and the substrate material to be patterned. The thin films patterned can be dielectrics, semiconductors, metals or organic and can be patterned as thin films or individual layers. Imprint lithography is particularly useful in roll-to-roll processing since it has a higher throughput, can handle wide substrates, and does not rely on optical flatness of the substrate to provide high resolution. However, the limitation of this implementation is related to the fact that in order to create the lexicon of two-port devices in the PIRM structure, an embossed mask with as many as seven discrete heights is needed. Consequently, an embossed mask with this number of heights puts a larger burden on the mask mastering, etching and imprinting processes.
Accordingly, what is needed is a method and system for fabricating a plurality of thin-film devices that overcomes the above referenced problems related to the PIRM fabrication process. The method and system should be simple, inexpensive and capable of being easily adapted to existing technology. The present invention addresses these needs.